Focus control apparatus

ABSTRACT

An imaging apparatus includes an imaging optical system, an imaging element acquiring an image of an object, a unit that acquires distance information corresponding to distance between the imaging optical system and the object, a unit that generates a map information corresponding to the image based on the distance information, a unit that is able to detect touch operation of a user on a display unit displaying the image and that detects a position in the image corresponding to a position touched by the user, and a control unit configured to acquire the distance information at the position of the acquired image from the map information to set the position as a focus point according to the acquired distance information, or configured to display, on the display unit, an enlarged image obtained by cutting an area of part of the image including the position.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 15/004,271,filed Jan. 22, 2016, the entire disclosure of which is herebyincorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an imaging apparatus and a method ofcontrolling the imaging apparatus.

Description of the Related Art

Conventionally, a technique of pressing a display screen to set a focusarea (hereinafter, also referred to as “AF point” or “focus point”) isproposed in an imaging apparatus including a liquid crystal displaypanel provided with a touch panel. In Japanese Patent ApplicationLaid-Open No. 2005-078009, an area of part of an acquired image isenlarged and displayed to check the focus of the set AF point.

However, when the AF point is designated by a finger on the screen ofthe imaging apparatus, an intended object is not focused, or perspectiveconflict occurs in some cases. Although the AF point can be enlarged tocheck the focus in the technique described in Japanese PatentApplication Laid-Open No. 2005-078009, the entire screen needs to bedisplayed again if the intended part is not focused.

In recent years, a method of enlarging an image by identifying operationof spreading two fingers touching the image in multi-touch operation iswidely used. However, performing the multi-touch operation while usingthe imaging apparatus during imaging is difficult, and setting the AFpoint at a desired object position is troublesome.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an imaging apparatusand a method of controlling the imaging apparatus that can accuratelyfocus an object intended by a user with simpler operation.

According to one aspect of the present invention, there is provided animaging apparatus including an imaging optical system that forms anoptical image of an object, an imaging element that acquires an image ofthe object from the optical image, a distance information acquiring unitthat acquires distance information which is corresponding to distancebetween the imaging optical system and the object, map generation unitthat generates map information corresponding to the image based on thedistance information, a position detection unit that is able to detecttouch operation of a user on a display displaying the image and thatdetects a position in the image corresponding to a position touched bythe user, and a control unit configured to acquire the distanceinformation at the position of the acquired image from the mapinformation to set the position as a focus point according to theacquired distance information, or configured to display, on the displayunit, an enlarged image obtained by cutting an area of part of the imageincluding the position.

According to another aspect of the present invention, there is provideda method of controlling an imaging apparatus including an imagingoptical system that forms an optical image of an object, an imagingelement that acquires an image of the object from the optical image, adistance information acquiring unit that acquires distance informationwhich is corresponding to distance between the imaging optical systemand the object, and a position detection unit that is able to detecttouch operation of a user on a display unit displaying the image, themethod including generating a map information corresponding to the imagebased on the acquired distance information, displaying the acquiredimage on the display unit, detecting the touch operation of the user onthe display unit to acquire a position in the image corresponding to aposition touched by the user, acquiring the distance information at theposition of the acquired image from the map information, and setting theposition as a focus point according to the acquired distanceinformation, or displaying, on the display unit, an enlarged imageobtained by cutting an area of part of the image including the position.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating configuration of an imagingapparatus according to a first embodiment of the present invention.

FIGS. 2A and 2B are diagrams describing distance map used in the imagingapparatus according to the first embodiment of the present invention.

FIG. 3 is a flow chart illustrating a method of controlling the imagingapparatus according to the first embodiment of the present invention.

FIGS. 4A and 4B are diagrams describing election method of an AF pointin the method of controlling the imaging apparatus according to thefirst embodiment of the present invention.

FIG. 5 is a diagram describing a distance histogram used in the imagingapparatus according to the first embodiment of the present invention,.

FIGS. 6A, 6B and 6C are diagrams describing types of peak patterns ofthe distance histogram.

FIG. 7 is a diagram describing an example of a d of detecting a peak ofthe distance histogram.

FIGS. 8A and 8B are diagrams describing an enlargement process of animage when the distance histogram indicates a single peak pattern.

FIGS. 9A and 9B are diagrams describing an enlargement process of animage when the distance histogram indicates a multi-peak pattern.

FIGS. 10A and 10B are diagrams describing a selection method of an AFpoint from an enlarged image in the method of controlling the imagingapparatus according to the first embodiment of the present invention.

FIGS. 11A and 11B are diagrams describing an example of occurrence ofperspective conflict in the AF point.

FIG. 12 is a schematic view of a display screen illustrating a method ofcontrolling an imaging apparatus according to a second embodiment of thepresent invention.

FIGS. 13A and 13B are diagrams illustrating an example of a distancehistogram displayed in a method of controlling an imaging apparatusaccording to a third embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawing.

First Embodiment

An imaging apparatus and a method of driving the imaging apparatusaccording to a first embodiment of the present invention will bedescribed with reference to FIGS. 1 to 10B.

FIG. 1 is a block diagram illustrating configuration of the imagingapparatus according to the present embodiment. FIGS. 2A and 2B arediagrams describing a distance map used in the imaging apparatusaccording to the present embodiment. FIG. 3 is a flow chart showingoperation of the imaging apparatus according to the present embodiment.FIGS. 4A and 4B are diagrams describing a selection method of an AFpoint in a method of controlling the imaging apparatus according to thepresent embodiment. FIG. 5 is a diagram describing a distance histogramused in the imaging apparatus according to the present embodiment. FIGS.6A to 6C are diagrams describing types of peak patterns of the distancehistogram. FIG. 7 is a diagram describing an example of a method ofdetecting a peak of the distance histogram. FIGS. 8A and 8B are diagramsdescribing an enlargement process of an image when the distancehistogram indicates a single peak pattern. FIGS. 9A and 9B are diagramsdescribing an enlargement process of an image when the distancehistogram indicates a multi-peak pattern. FIGS. 10A and 10B are diagramsdescribing a selection method of the AF point from an enlarged image inthe method of controlling the imaging apparatus according to the presentembodiment.

First, a structure of the imaging apparatus according to the presentembodiment will be described with reference to FIG. 1.

As illustrated in FIG. 1 an imaging apparatus 10 according to thepresent embodiment includes an imaging optical system 101, a focuscontrol unit 102, an imaging sensor 103, an image processing unit 104, adistance information generation unit 105, a memory 106, a recordingprocessing unit 107, a recording medium 108 and a ROM 109. The imagingapparatus 10 also includes a system control unit 110, a displayprocessing unit 111, a display unit 112, a position detection unit 113,a touch panel 114 and a bus 115.

The imaging sensor 103 is a solid-state imaging device, such as a CMOSsensor, and is configured to acquire an image of an object (hereinafter,also referred to as “object image”). A sensor for phase differencedetection is embedded in the imaging sensor 103, and information ofdistance from the object imaged based on a phase difference signaloutput from the imaging sensor 103 can, also be acquired. That is, theimaging sensor 103 also has functions as a distance informationacquiring unit. The imaging optical system 101 is configured to form anoptical image of the object on the imaging sensor 103 and includes afocus position control mechanism. The focus control unit 102 is acontroller configured to control operation of the focus position controlmechanism of the imaging optical system 101.

The distance information generation unit 105 is a circuit or a processorconfigured to calculate the information of distance from the objectbased on the phase difference signal output from the imaging sensor 103.The calculated distance information of the object is stored in thememory 106. The image processing unit 104 is a circuit or a processorconfigured to digitize an image signal output from the imaging sensor103 to apply a predetermined process to the image signal. The processedimage data is temporarily stored in the memory 106.

The memory 106 is an internal storage device including a semiconductormemory such as a DRAM. The memory 106 stores recording data generated bythe recording processing unit 107, a program for controlling the imagingapparatus 10, and GUI (graphical user interface) data, such as images,characters and icons, displayed on the display unit 112.

The recording processing unit 107 is a circuit or a processor configuredto read and convert the image data and the distance information of theobject stored in memory 106 into a predetermined recording format and towrite the data and the information in the recording medium 108. Althoughnot particularly limited, the recording medium 108 can be, for example,a memory card using a non-volatile semiconductor memory such as an SDmemory card.

The system control unit 110 is a control unit (CPU), a circuit or aprocessor that controls the entire imaging apparatus 10. The ROM(read-only memory) 109 is configured to store a control program,character fonts and icon resource data.

The display unit 112 includes a display device such as a liquid crystalpanel. The touch panel 114 is mounted on a display surface, such as aliquid crystal panel, of the display unit 112. The display processingunit 111 is a circuit or a processor configured to execute a process ofdisplaying a video stored in the memory 106 and information of icons andcharacters on the display unit 112.

The position detection unit 113 is a circuit or a processor configuredto detect and output, to the system control unit 110, touch operation ofthe user on the touch panel 114 and the position pressed by the fingerof the user.

The bus 115 is a path for connecting the modules to exchange databetween the modules. The system control unit 110 transmits predeterminedcontrol signals to the modules through the bus 115 to control the entireimaging apparatus 10.

Before describing specific operation of the imaging apparatus 10according to the present embodiment, an example of the distanceinformation generated by the distance information generation unit 105will be described with reference to FIGS. 2A and 2B.

FIG. 2A is a schematic diagram illustrating positional relationshipbetween the imaging apparatus 10 and objects 210, 211 and 212. Distancesfrom the imaging apparatus 10 to the objects 210, 211 and 212 aredistances L1, L2 and L3, respectively.

As described, the imaging sensor 103 can divide and import signals ofpixels of an imaging surface to acquire phase difference information forAF (auto focus) of each pixel. Based on the phase difference informationacquired from the imaging sensor 103, the distance informationgeneration unit 105 generates the information of distance to the objectbeing imaged at predetermined resolving power. A well-known techniquecan be applied to generate the distance information based on the imagingsurface phase difference detection, and the details will not bedescribed here.

FIG. 2B is a schematic view of a distance map indicating the acquireddistance information by two-dimensional image information (mapinformation). In a distance map 215 of FIG. 2B, the taken image isdivided into 9×9 unit areas, and the unit areas are colored in differentpatterns corresponding to the distances to the object. Distance data220, 221 and 222 are data indicating distances from the objects 210, 211and 212 of FIG. 2A. The right side of FIG. 2B illustrates relationshipbetween the patterns of the areas in the distance map 215 and thedistance from the imaging apparatus to the objects.

The distance data can be detected for each pixel of the imaging sensor103. However, to improve the processing performance, a distance mapallocating one distance data to every N×N pixels of the imaging sensor103 can be generated in an initial state, for example. When the totalnumber of pixels of the imaging sensor 103 is H×V, the resolving powerof the distance map in the initial e is (H/N)×(V/N). The resolving powerof the distance map 215 can be changed in the setting of the systemcontrol unit 10.

The format of the distance data indicated on the distance map 215 is notlimited to the example described above, and data in an arbitrary formatcan be used as long as the data indicates the distances between theimaging apparatus 10 and the objects.

The distance map data generated by the distance information generationunit 105 is temporarily stored in a predetermined area of the memory106. The system control unit 110 controls the recording processing unit107 to convert the distance map data into a predetermined recordingformat along with the image data stored in the memory 106, and the datais recorded in the recording medium 108. The image data and the distancemap data are generated based on signals at the same timing in theimaging sensor 103.

Operation of the imaging apparatus according to the present embodimentwill be described with reference to FIGS. 3 to 10B.

The imaging apparatus 10 according to the present embodiment can becontrolled according to, for example, the low chart illustrated in FIG.3.

In step S301, power is applied through an operation unit notillustrated, and the operation of the imaging apparatus 10 is started.

In step S302, an object image during imaging that enters the imagingsensor 103 through the imaging optical system 101 is converted by theimaging sensor 103 into an electrical signal, and the electrical signalis input to the image processing unit 104. The image processing unit 104applies predetermined image processing to the image data, and theprocessed image data is stored in the memory 106. The display processingunit 111 reads the image data stored in the memory 106, and the displayunit 112 displays the image data.

The imaging sensor 103 also outputs a focus detection signal for AF(phase difference information described above), and the signal is inputto the distance information generation unit 105. The distanceinformation generation unit 105 generates a distance map based on thefocus detection signal and stores the distance map in the memory 106.

In step S303, when touch operation for the touch panel 114 by a fingerof the user or the like is detected, the touch panel 114 outputs asignal corresponding to the operation to the position detection unit113. Examples of the signal output by the touch panel 114 include asignal indicating a pressed state of the finger and a signal indicatingthe position when the touch panel 114 is pressed.

The position detection unit 113 receives the signal according to thepress from the touch panel 114 at a predetermined sampling rate. Theposition detection unit 113 outputs, to the system control unit 110,data indicating the pressed state of the touch panel 114 and dataindicating a two-dimensional position on the screen of the display unit112 when the touch panel 114 is pressed.

The system control unit 110 detects an operation state of the finger forthe touch panel based on the data received from the position detectionunit 113. Examples of the operation state of the finger include a statethat the finger touches the touch panel 114 (hereinafter, referred to as“press”), a state that the finger is separated from the touch panel 114(hereinafter, referred to as “un-press”) and a state that the finger ismoving while pressing the touch panel 114 (hereinafter, referred to as“move”).

If the system control unit 110 determines that the operation state is“press”, the process moves to step S304. On the other hand, if theoperation state is not “press”, the system control unit 110 waits forthe next data from the position detection unit 113 in step S303.

In step S304, the system control unit 110 determines whether theoperation state of the finger is “move” based on the data received fromthe position detection unit 113. As a result, if the system control unit110 determines that the operation state of the finger is “move”, theprocess moves to step S307.

In step S307, the system control unit 110 determines whether the objectimage displayed on the display unit 112 is in an enlarged display state.The enlarged display state is a state in which an area of part of theobject image is enlarged and displayed in step S308 described later. Asa result, if the system control unit 110 determines that the objectimage is in the enlarged display state, the enlarged display image ismoved according to the moved amount and the direction. On the otherhand, if the system control unit 110 determines that the object imagedisplayed on the display unit 112 is not in the enlarged display state,the current state is held, and the process returns to step S302.

If the system control unit 110 determines that the operation state ofthe finger is not “move” in step S304, the process moves to step S305.

In step S305, the distance map data generated by the distanceinformation generation unit 105 and stored in the memory 106 isanalyzed. An analysis method of the distance map data in step S305 willbe described with reference to FIGS. 4A to 5.

As illustrated in FIG. 4A, the screen during imaging (object image 401)displayed on the display unit 112 includes objects 403, 404 and 405. Thedistance map corresponding to the object image 401 is a distance map 402illustrated in FIG. 4B. In the distance map 402, distance data 406, 407and 408 indicate distances to the objects 403, 404 and 405,respectively.

When a finger 409 of the user presses the touch panel 114 mounted on thedisplay unit 112 that displays the object image 401, the system controlunit 110 detects the pressed position on the object image 401 throughthe touch panel 114 and the position detection unit 113. For example, apoint A is the detected press position (hereinafter, referred to as“press position A”) in the object image 401 of FIG. 4A.

The system control unit 110 sets a predetermined area P around the pressposition A. The area on the distance map 402 corresponding to the area Pis an area 421 of FIG. 4B. In the example of FIG. 4B, the area 421includes 25 unit areas, and the distance data indicating the distanceinformation to the object image is associated with each unit area.

The system control unit 110 analyzes the distance data in the area 421to generate a distance histogram as illustrated in FIG. 5. Morespecifically, the system control unit 110 compiles the numbers of unitareas in the area 421 for each distance indicated by the distance dataand arranges the numbers of unit areas for each distance in ascendingorder from the minimum value to the maximum value of distance. Forexample, the numbers of unit areas corresponding to each distance in thearea 421 of FIG. 4B are as illustrated in Table 1, and the numbers areconverted into a graph to obtain the distance histogram illustrated inFIG. 5.

TABLE 1 Distance Degree 0 m-1 m 0 1 m-2 m 7 2 m-3 m 0 3 m-4 m 13 4 m-5 m0 5 m-6 m 0 6 m- 5

In step S306, the system control unit 110 determines whether a focuspoint (AF point) can be confirmed based on the generated distancehistogram.

The system control unit 110 first classifies the distance data intothree distance patterns based on the generated distance histogram. Afirst pattern of the three distance patterns is a single peak pattern. Asecond pattern is a multi-peak pattern. A third pattern is singledistance pattern.

These three distance patterns will be described with reference to FIGS.6A to 6C. FIG. 6A is a schematic diagram of a distance histogram of thesingle peak pattern. As illustrated in FIG. 6A, the single peak patternincludes data section indicating a single peak, and a proportion of adegree of the data section indicating the single peak in the entire datais smaller than a predetermined value. Therefore, a considerable numberof distance data other than the single peak is also included in thiscase. FIG. 6B is a schematic diagram of a distance histogram of themulti-peak pattern. As illustrated in FIG. 6B, the multi-peak patternincludes a plurality of data sections indicating peaks. FIG. 6C is aschematic diagram of a distance histogram of the single distancepattern. The single distance pattern includes a data section indicatinga single peak, and a proportion of a degree of the data sectionindicating the single peak in the entire data is greater than thepredetermined value. Therefore, this case includes few distance dataother than the single peak.

The following method can be used for the peak detection in the distancehistogram, for example. However, the method of the peak detection is notlimited to the following method, and other well-known methods can alsobe used.

The system control unit 110 first calculates an average value of thedegrees in the distance histogram. For example, a degree M is theaverage value in the distance histogram of FIG. 7. The system controlunit 110 then calculates a difference between the degree of eachdistance and the average value M. The system control unit 110 detectsthat the distance is a peak if the difference is equal to or greaterthan a predetermined value. For example, if the degree M of average anda predetermined value D of difference are values as illustrated in theexample of FIG. 7, the distance (3 m to 4 m) with a degree equal to orgreater than (M+D) s detected as a peak.

As a result of the peak detection, if the detected pattern is the singledistance pattern, it is determined that the AF point is confirmed. Thedistance information of the data section corresponding to the detectedpeak is stored in the system control unit 110, and the process moves tostep S309.

On the other hand, if the detected pattern is one of the single peakpattern and the multi-peak pattern, the system control unit 110determines that the AF point is not confirmed, and the process moves tostep S308. In step S308, a process of enlarging part of the image todisplay the image again is executed to confirm the AF point.

The process executed when the determined pattern is the single peakpattern as a result of the peak detection in step S306 will be describedwith reference to the schematic diagrams of FIGS. 8A and 8B. FIG. 8A isa schematic diagram of s distance map, and FIG. 8B is a distancehistogram generated based on the distance map of FIG. 8A.

In a distance map 600 of FIG. 8A, an area 602 is an area set by thesystem control unit 110 around a point pressed by a finger of the userin selecting the AF point. FIG. 8B illustrates a distance histogramgenerated by the system control unit 110 based on distance data of unitareas in the area 602.

The system control unit 110 uses the distance histogram of FIG. 8B todetect the above peak pattern, and as a result, the detected peakpattern is a single peak pattern with a peak 601.

When the single peak 601 is detected, the system control unit 110extracts the unit area indicating the data section (3 m-4 m)corresponding to the peak 601 from the distance snap 600 and calculatesa center of gravity of the extracted unit area. The system control unit110 sets a cut area around the calculated center of gravity. In thiscase, a cut size is calculated such that a proportion of the unit areaindicating the distance information corresponding to the data section ofthe peak 601 in the cut area is about a predetermined value, such asabout 50%. In the example of FIG. 8A, the system control unit 110 sets acut area 603 indicated by a dotted line.

The process executed when the determined pattern is the multi-peakpattern as a result of the peak detection in step S306 will be describedwith reference to the schematic diagrams of FIGS. 9A and 9B. FIG. 9A isa schematic diagram of distance map data, and FIG. 9B is a distancehistogram generated bayed on the distance map data of FIG. 9A.

FIG. 9A illustrates the distance map 402 corresponding to the image 401during imaging illustrated in FIG. 4A, and an area 421 is an area set bythe system control unit 110 according to the press position A. FIG. 9Billustrates a distance histogram generated by the system control unit110 based on distance data of unit areas in the area 421. The distancehistogram of FIG. 9B is classified into the multi-peak pattern with aplurality of peaks 701 and 702.

When the multi-peak pattern is detected, the system control unit 110extracts the unit areas indicating the data section (1 m-2 m)corresponding to the peak 701 and indicating the data section (3 m-4 m)corresponding to the peak 702 from the distance map data. The systemcontrol unit 110 calculates a center of gravity of the extracted unitareas and sets a cut area around the calculated center of gravity. Inthis case, a cut size is calculated such that a proportion of the unitareas indicating the distance information corresponding to the datasections of the peaks 701 and 702 in the cut area is about apredetermined value, such as about 50%. In the example of FIG. 9A, thesystem control unit 110 sets a cut area 704 indicated by a dotted line.

After the cut area is set in this way, the process returns to step S302,and an enlarged image is displayed. More specifically, the systemcontrol unit 110 issues an instruction to the display processing unit111 to read the data corresponding to the cut area from the image duringimaging stored in the memory 106 to execute an enlargement process. Thedisplay processing unit 111 applies the enlargement process to the dataread from the memory 106 and outputs the data to the display unit 112.As a result, part of the image during imaging corresponding to the area603 is enlarged and displayed on the display unit 112.

Whether to confirm the AF point or to display the enlarged image can beautomatically determined according to the peak pattern of the distancehistogram, and this can eliminate a step by the user enlarging a desiredposition to a desired size by performing pinch-out operation or the likeon the screen. Particularly, performing the pinch-out operation or thelike while holding the imaging apparatus is cumbersome and troublesome,and the method of the present embodiment is significantly useful.

FIG. 10A illustrates an enlarged image when the determined pattern isthe multi-peak pattern, and the image corresponding to the area 704 ofFIG. 9A is enlarged. An enlarged image 801 includes an object 802 and anobject 804.

After the enlarged image is displayed on the display unit 112 in stepS302, the process described above is applied to the enlarged image inthe following steps. More specifically, when the user touches the object802 in the enlarged image 801 by a finger, the press of the touch panelis detected in step S303. In step S304, the system control unit 110detects whether the operation is move operation. In step S305, distancemap data of the pressed area is analyzed.

In the example of FIG. 10A, a distance map corresponding to an area 803is analyzed. FIG. 10B illustrates a schematic diagram of the distancehistogram detected in the area 803.

In step S306, the system control unit 110 analyzes the peak pattern ofthe distance histogram detected in the area 803. The distance histogramof FIG. 10B includes a single peak, and the proportion of the degree ofthe distance of the peak in the entire data is greater than apredetermined number. Therefore, it can be determined that the patternis the single distance pattern, and the distance in area 803 issubstantially the same. As a result, the system control unit 110determines that the AF point is confirmed and stores the distanceinformation of the peak, and the process moves to step S309.

When the image of the set area is enlarged and displayed in step S308,it is desirable to acquire and display the image by controlling thefocus to focus the enlarged object. For example, in the case of thesingle peak pattern, the focus can be controlled according to thedistance of the peak of the distance histogram, and the objectpositioned at the peak distance can be focused when the image isenlarged and displayed. In the case of the multi-peak pattern, the focusis adjusted according to the distance of the maximum degree among theplurality of peaks, and the object positioned at the peak distance ofthe maximum degree is focused in the image when the image is enlargedand displayed. As a result, the visibility can be improved in theselection of the AF point in the enlarged image.

In step S309, the system control unit 110 uses the stored distanceinformation of the peak and issues an instruction of focus control tothe focus control unit 102. The focus control unit 102 controls theimaging optical system 101 focusing at the instructed distance. As aresult, an image focusing the object of the peak area can be acquiredand displayed on the display unit 112.

In this way, when an object area to be focused is selected by touchpanel operation in the imaging apparatus of the present embodiment, theobject area is automatically enlarged and displayed in an appropriatesize based on the distance data map. Therefore, the AF point can besimply and surely set. As a result, a convenient imaging apparatus withexcellent usability can be realized.

Second Embodiment

An imaging apparatus and a method of driving the imaging apparatusaccording to a second embodiment of the present invention will bedescribed with reference to FIGS. 11A to 12. The same constituentelements as in the imaging apparatus according to the first embodimentillustrated in FIGS. 1 to 10B are designated with the same referencesigns, and the description will not be repeated or will be simplified.

FIGS. 11A and 11B are diagrams describing an example of occurrence ofperspective conflict in the AF point. FIG. 12 is a schematic view of adisplay screen indicating a method of controlling the imaging apparatusaccording the present embodiment of the present invention.

The method of controlling the imaging apparatus according to the presentembodiment deals with a case in which selecting the AF point isdifficult even in the enlarged image in the method of driving theimaging apparatus according to the first embodiment. A characteristicpart of the method of driving the imaging apparatus according to thepresent embodiment will be described with reference to the drawings.

FIG. 11A is a schematic view illustrating an example of the enlargedimage, and FIG. 11B is a schematic diagram illustrating an example ofthe distance histogram used to generate the enlarged image of FIG. 11A.

In FIG. 11A, four belt-shaped areas 1102 with dense hatching indicate anobject corresponding to the peak positioned in a data section (2 m-3 m)of the distance histogram of FIG. 11B. Four belt-shaped areas 1103 withsparse hatching indicate an object corresponding to the peak positionedin a data section (4 m-5 m) of the distance histogram of FIG. 11B. Insuch a case, even if an attempt is made to press the enlarged image 1101by a finger to set the AF point, accurately pressing and selecting oneof the areas 1102 and the areas 1103 is difficult because the areas 1102and 1103 are thin and adjacent to each other.

Therefore, a GUI is displayed on one of the operation unit notillustrated and the display unit 112 to allow the user to switch thedisplay mode in the imaging apparatus according to the presentembodiment.

For example, when the system control unit 110 detects operation of oneof the operation unit and the touch panel 114 and further detects thatthe operation is operation of a display mode switching button, thesystem control unit 110 changes the display of the display unit 112 to aconfiguration such as in a screen 1201 of FIG. 12.

The screen 1201 includes an enlarged image 1202 and a distance histogram1203. The enlarged image 1202 is an enlarged image (equivalent to theenlarged image 801) described in the first embodiment and is generatedby the display processing unit 111. The distance histogram 1203 is adistance histogram that is a basis of the enlarged image. The systemcontrol unit 110 calculates the distance histogram data to generate GUIdata as illustrated in FIG. 12 by using the calculated distancehistogram data and stores the GUI data in the memory 106. The displayprocessing unit 111 reads the GUI data stored in the memory 106 anddisplays the GUI data on the display unit 112.

The user can select the object by pressing the distance histogram 1203instead of the enlarged image 1202. For example, to select the object ofthe area 1102 as an AF point, the user presses a data section 1204 ofthe distance histogram 1203 corresponding to the area 1102. In this way,a desired object can be easily selected as an AF point. The detection ofthe press position and the like are the same as in the first embodiment,and the description will not be repeated here.

The color and the pattern may be changed for each data section of thedistance histogram 1203 as in FIG. 12, and the same color and patternmay be provided to the object positioned at the distance correspondingto each data section. In this way, the relationship between the datasection of the distance histogram 1203 and the object of the enlargedimage can be clearly indicated, and the user can easily designate thedata section corresponding to the desired object.

In this way, according to the present embodiment, a desired object canbe easily selected as an AF point even if perspective conflict occurs inthe focus area selected by the user.

Third Embodiment

An imaging apparatus and a method of driving the imaging apparatusaccording to a third embodiment of the present invention will bedescribed with reference to FIGS. 13A and 13B. The same constituentelements as in the imaging apparatus and the method of driving theimaging apparatus according to the first and second embodimentsillustrated in FIGS. 1 to 12 are designated with the same referencesigns, and the description will not be repeated or will be simplified.

FIGS. 13A and 13B are diagrams illustrating an example of a distancehistogram displayed in the method of controlling the imaging apparatusaccording to the present embodiment.

The method of driving the imaging apparatus according to the presentembodiment deals with more accurate focusing, in which the accuracy ofthe distance map data is improved in stages.

In the method of driving the imaging apparatus according to the secondembodiment, a GUI including the enlarged image 801 illustrated in FIG.10A and including distance histogram (FIG. 13A) that is a basis of theenlarged image 801 is displayed on the display unit 112, for example.

in this case, the user selects the data section corresponding to thedistance (1 m to 2 m) as an AF point according to the method of drivingthe imaging apparatus of the second embodiment. However, the user maydesire to set the AF point based on a more accurate range. Therefore,the following process is executed to enable more accurate focusing inthe method of driving the imaging apparatus according to the presentembodiment.

When the system control unit 110 detects that the enlarged image 801 ispressed, the system control unit 110 displays the distance histogram ofFIG. 13A as a GUI and measures the elapsed time from the start of thepress.

If a data section of the distance histogram displayed as the GUI ispressed before the elapsed time from the press of the enlarged image 801reaches a predetermined time, the process continues according to thedriving method of the second embodiment.

If the press of the distance histogram is not detected before theelapsed time from the press of the enlarged image 801 exceeds thepredetermined time, the system control unit. 110 instructs the distanceinformation generation unit 105 to set a smaller unit for the distanceinformation to be generated. The distance information generation unit105 regenerates the distance map data according to the newly set unit.Based on the regenerated distance map data, the system control unit 110generates a distance histogram with a higher resolution of data section.

FIG. 13B illustrates an example of the regenerated distance histogram.Although the data sections are divided on a basis of 1 m in the distancehistogram of FIG. 13A, the data sections are divided on a basis of 0.2 min the distance histogram of FIG. 13B, and the accuracy is five-fold.

The display processing unit 111 displays a GUI of the regenerateddistance histogram on the display unit 112. The user can press aspecific data section of the displayed distance histogram by a finger tofocus a desired point of the object.

In this way, according to the present embodiment, the AF point can beset on a desired object at a higher accuracy.

Modified Embodiments

The present invention is not limited the embodiments, and variousmodifications can be made.

For example, the configuration of the imaging apparatus according to thefirst embodiment is just an example, and the imaging apparatus in whichthe present invention can be applied is not limited to the configurationillustrated in FIG. 1.

Other Embodiments

Embodiments of the present invention can also be realized by a computerof a system or apparatus that reads out and executes computer executableinstructions (e.g., one or more programs) recorded on a storage medium(which may also be referred to more fully as a ‘non-transitorycomputer-readable storage medium’) to perform the functions of one ormore of the above-described embodiments and/or that includes one or morecircuits (e.g., application specific integrated circuit (ASIC)) forperforming the functions of one or more of the above-describedembodiments, and by a method performed by the computer of the system orapparatus by, for example, reading out and executing the computerexecutable instructions from the storage medium to perform the functionsof one or more of the above-described embodiments and/or controlling theone or more circuits to perform the functions of one or more of theabove-described embodiments. The computer may comprise one or moreprocessors (e.g., central processing unit (CPU), micro processing unit(MPU)) and may include a network of separate computers or separateprocessors to read out and execute the computer executable instructions.The computer executable instructions may be provided to the computer,for example, from a network or the storage medium. The storage mediummay include, for example, one or more of a hard disk, a random-accessmemory (RAM), a read, only memory (ROM), a storage of distributedcomputing systems, an optical disk (such as a compact disc (CD), digitalversatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, amemory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2015-011574, filed Jan. 23, 2015, which is hereby incorporated byreference herein in its entirety.

1. A focus control apparatus comprising: one or more processors; and amemory storing instructions which, when the instructions are executed bythe one or more processors, cause the focus control apparatus tofunction as: an acquiring unit that acquires an image of objectscaptured by an imaging element and map information corresponding todistance information between the imaging element and the objects; ageneration unit that generates a distance histogram based on the mapinformation; a display control unit that displays, on a display unit,the image and the distance histogram generated by the generation unitand corresponding to the image; a detection unit that detects touchoperation by a user for the distance histogram displayed on the displayunit; and a setting unit that sets as a focus area, an area indicatingthe distance information corresponding to a data section of the distancehistogram touched by the user in the image.
 2. The focus controlapparatus according to claim 1, wherein the display control unitdisplays the image and the distance histogram simultaneously.
 3. Thefocus control apparatus according to claim 1, wherein the displaycontrol unit displays the distance histogram in which the data sectionsare described differently.
 4. The focus control apparatus according toclaim 1, wherein the display control unit displays the distancehistogram in which the data sections are described at different colorsor patterns, and wherein, in the image, the display control unitprovides the same color or patterns to the objects positioned at thedistance corresponding to each data section.
 5. The focus controlapparatus according to claim 1, wherein the display control unitdisplays the distance histogram in which each of the data sections hasdifferent graphical user interfaces.
 6. The focus control apparatusaccording to claim 1, wherein the setting unit automatically sets thefocus area based on a distribution of the distance histogram generatedby the generation unit.
 7. The focus control apparatus according toclaim 1, wherein the generation unit generates the distance histogramseach having different resolution.
 8. The focus control apparatusaccording to claim 1, further comprising: a focus control unit thatcontrols an operation of a focus position control mechanism of animaging optical system leading optical images of the objects to theimaging element based on the focus area set by the setting unit.
 9. Afocus control method comprising: acquiring an image of objects capturedby an imaging element and map information corresponding to distanceinformation between the imaging element and the objects; generating adistance histogram based on the map information; displaying, on adisplay unit, the image and the distance histogram generated by thegeneration unit and corresponding to the image; detecting touchoperation by a user for the distance histogram displayed on the displayunit; and setting as a focus area, an area indicating the distanceinformation corresponding to a data section of the distance histogramtouched by the user in the image.